Scrap Silver Solder

[firbikrhd1]

My Dad just handed me about two pounds of scrap silver solder of unknown alloy. According to Dad it was saved by my grandfather who made repairs to the wiring harness conduits of radial engines shortly after World War II. Apparently he desoldered (Brazed) the conduits at the joints, removed various dings and dents in them and later resoldered (Brazed) them for return to service. I believe these conduits were made of stainless but am not certain. Anyone have any idea of what alloy it might be? How about it's value for silver content? Can it be used as silver solder again or would it be too contaminated to reuse? Any information from those who may have done similar work would be appreciated.
Thank you!

[Evan]

If it is true silver brazing solder then it is around 50% or greater silver content. It is definitely worth some money in that case. There are plenty of foundries that will buy scrap like that at pretty good prices. Naturally there will be a discount on the market price. You can either take cash or they will cast you certified bars and take payment by keeping some of the silver. You could probably end up with half a dozen certified one ounce bars. Today's price on silver is 35.42 per troy ounce. There are 14.583 troy ounces in a pound.

[darryl]

How about fluxing up a two-part thing and seeing how well it will solder? You might try mechanically de-oxidizing it- grind a small notch in the end of a used hacksaw blade and scrape a few pieces clean. You might have a pretty good value there just for its intended purpose-

[Evan]

Come to think about it, it is probably very high silver content. During WWII copper was in much higher demand than silver. During the war copper buss bars in power plants and factories all around the US were temporarily replaced by solid silver buss bars cast from the Treasury stocks at Fort Knox. Silver is a pretty good replacement for copper in many applications if cost is no object. They would have increased the silver content to save on the copper. You could ask a local jeweller where you can get it assayed and refined.

[aostling]

During WWII copper was in much higher demand than silver. During the war copper buss bars in power plants and factories all around the US were temporarily replaced by solid silver buss bars cast from the Treasury stocks at Fort Knox.

Scroll down here http://www.darkroastedblend.com/2009...and-power.html for the photos of the "gothic" BC Hydro plant at Buntzen Lake. I wonder if there are any of those silver bus bars in that abandoned plant.

[whitis]

I have never worried about deterioration with age of solid wire or flux core solders though I wouldn't normally be dealing with stuff 75 years old but might have some electronics solder which is 35. Solder paste (for surface mount electronics) does go off, quickly. Age of electronics copper/tin surfaces being soldered with can be an issue since you are limited in the use of harsh fluxes.

Depending on the application, any possible lead content can be an issue if it is used in potable water plumbing, moonshine stills, food/pharmacuetical processing, toys, bird toys/cages, jewelry, or any electronics device (even if it isn't used to solder the electronics which it isn't suitable for anyway) subject to RoHS regulations.

Paint stores/hardware stores have lead test kits.

In theory it would be worth more for its original application but given the age, unspecified alloy, and very picky lead-free requirements in many applications it might go for significantly less than the silver content is worth if you tried to sell it unless, perhaps, you sold it to someone doing vintage restorations who might actually appreciate solder which qualifies for a senior citizen discount.

[darryl]

I've been to that one at Buntzen lake. There's another one near Yarrow, BC- not a power generating station, but a transformer station I believe, to run the electric railway that used to be there. People live in that building now. Some decades ago, and after it had been de-commissioned, there were buss bars laying around- not silver ones though. I also got to visit the old CHWK transmitter site- lots of goodies laying around there.

Yeah, there's some genuine architecture in those buildings.

[Black_Moons]

Try melting some and see what tempature it melts at.

the low % silver alloys melt at soldering iron temps
the 50% alloys melt at like 1100f (awhile below the melting point of copper/brass)

Note theres also 56% alloys that had cadnium in em.. still sold today actualy.

[Evan]

I just looked up the recommended silver brazing solders for thin stainless steel sections in the Handy Harman Brazing Book. There are two main types, Lithobraze 720 and Lithobraze 925. They are 71.7% and 92.5% silver respectively.

[GKman]

I just sold some junk jewelry metal. The jewelry store/buyer had a mass spectrograph or something to test scrapings on the spot. Check around for coin buyers.

[gary350]

I have several rolls of silver solder my 87 year old father gave to me. It solders just fine, no different than brand new silver solder.

I save scrap pieces after soldering. I also save silver motor starter contacts. The local coin shop in town is the best place to sell it. They do a test that takes about 45 seconds then make an offer according to how much silver it contains.

There are 3 coin shops in town and 2 places that buy gold and silver. I get a quote form all 5 and so far Jim's Coin Shop pays the most.

Last time I saved about 1/4 cup of scrap silver and sold it was about 4 years ago.

[kbertoson]

The radial engine wire harness tube is brass I think. When I worked in a radial engine shop in the late 1970's we had a guy that stripped them and fixed the dents and they went to Miami for chrome plate. I worked on magnetos not the harness

[kbertoson]

Also the points in the large radial engine magnetos are platinum. If you run across any old radial engine magnetos. Never know what you guys may find at garage sales.